What to Look for in a Case Sealer Part 1 – Belts

Case sealers whether semi or fully automatic are relatively simple machines. They are basically a table with a conveyor and tape head or glue gun. However, the simplicity of these machines does not mean that they are all the same.

Belts are one of the main things that differentiate different case sealers. They are extremely important as they do most of the heavy lifting by driving the case across the machine for sealing. Although it’s hard to compare the quality of the actual belt unless you’re in front of the machine, things we can look at are belt orientation and belt drive.

There are 2 main types of belt orientations, bottom drive and side drive. Bottom drive are when cases will travel on top of the belts while the box will travel between the belts on a side belt drive. Top belts can also come to play but are usually found in conjunction with either a bottom belt or side belt.

So which is better?

Generally, side belts are better in terms of securely holding the case for a good seal. Bottom belts are also more at the mercy of the case size footprint and the weight of the product as it relies on friction for moving the case properly. Therefore bottom belt machines are especially less effective for cases with lighter product and cases that are narrow, short or are a tower type of case.

Conveyor design is the next area for consideration. Number of motors and horse power is a simple factor to look at in terms of torque power and the wear and tear factor given the case weight and/or size. Most sealers use fractional gear motors. Often they use two motors, one for each conveyor. This is adequate for short distances, but the longer the conveyor the greater the risk of introducing a skew to a case if the motors are out sync.

Finally, the construction design elements like, size of drive both height of belts along with diameter of drive pulleys and belt support. Larger drive pulleys provide more surface contact with the belt which is superior drive. Also belt height provides more contact with the case for better overall transport. You will also want to look at how the belts are supported. Having a strong support behind the belts is good but If they aren’t compliant, it will not be able to adapt to the natural variances in your corrugated. This can lead to either case jams or worse product or even machine damage.